Thrust bearings have enumerable applications where a force must be borne along a force vector between two members, with one member movable relative to the other. Conventional thrust bearings typically include a plurality of roller elements such as ball bearings housed within races formed in a pair of opposing members. The opposing members are movable relative to one another by virtue of the rolling contact of the plurality of roller elements rotating within the races formed between the opposing members.
Due to the relatively large forces which are borne by thrust bearings, reduction in the friction within the bearings is critical to ensure relative movement of the opposing members while under load. For example, U.S. Pat. No. 4,523,863 to Okoshi discloses a thrust ball bearing using multiple ball bearings and having opposing races with slightly larger cross-sectional radii to minimize contact, and therefore friction, between the balls and the races.
U.S. Pat. No. 2,244,434 to Shaw discloses a supporting roller bearing wherein a pair of cylindrical rollers are supported by three sets of anti-friction bearings, with each roller element supporting two of the three sets of bearings. However, since each roller element engages two anti-friction bearings, increased friction is exhibited within the system. In addition, the offset nature of the rollers relative to the anti-friction bearing applies lateral forces to the rollers, which also increases the friction present in the system.
U.S. Pat. No. 4,297,913 to Garbo discloses a remote control having a push-pull blade with captive rolling elements. The rolling elements are in contact with one another as well as with outer races formed within a tubular sheath. The rolling elements are retained within openings in the push-pull blade such that they are maintained in rolling contact with one another. However, Garbo is not directed to a thrust bearing arrangement. The primary forces exhibited upon the system are along the longitudinal axis of the tubular sheath, and consequently the rolling elements are arranged along an axis which is orthogonal to the force vector. In addition, the manner in which the rolling elements are retained by the push-pull blade may not adequately house the rolling elements in operation, and may introduce additional friction in certain applications.
Therefore, a substantial need exists for a thrust bearing arrangement which is capable of permitting the relative movement of two members while bearing a load along a force vector applied between the members. In addition, a substantial need exists for such a bearing arrangement which exhibits reduced friction in a simple and economical manner.